Help, mast step repair

Thread starter #1
Hi, my mast step is leaking, so i have installed an inspection port to try to fix it from the inside. When i poor some water down the mast step i can see its leaking from the bottom, but it is also about half an inch of water left when it has been standing there for some hours.

My problem is the donut thing around the bottom of the mast step, i have read on this forum that it should be removed and you should poor some epoxy down the "gap" instead, but i don't know if this is true? I tried to remove some of the donut, it worked a little bit, but to remove it all would take many hours of hard work. Is there any good techniques for this? Or could i just leave the donut as is, and wrap some layers of fiberglass around the mast step?? And maybe poor some epoxy down where it is leaking from?

Never done a repair like this so i appreciate all the help i can get :)

Also uploaded some pics so you can see where its leaking from. I think the boat is from 1970-1980.


Voodoo 158546

Hard hiking at the end of a 3hr race, killer
It's not uncommon for the mast pot to become worn. No stress.
Pouring epoxy in the crack is a 50/50 affair...for the gear to truly bond the accepting surfaces must be exposed, dried, keyed up, cleaned.
Pouring is a quick/ lazy 'fix'.
You don't have to remove the 'doughnut' but for peace of mind - if it were me - I'd suggest removing a half inch either side of the apparent gap..( you will get a better picture of the wound, it may be more or less than you imagine).
Tools ? - a sharp chisel, a dremel, some 80 grit paper. Won't take much effort to reveal the extent of the damage.
Once it's clear what's what, it's a straightforward wet lay up of cloth and resin ( epoxy is way better - stronger, kinder to the user, much less prone to h20 uptake later, more additives available ).
It's important to thouroughly dry the area, first you need to clean it all with fresh water then dry..a hot air gun for fifteen minutes is king here.
May I suggest you bother to get some cloth for epoxy rather than chop strand.'ll only need about a half a metre but prolly only be able to purchase a sq. metre. Cool, save some for your next fix !
It's important also to rid the keyed up area of dust - hoover.
Clean it all some more with acetone on a clean rag or blue auto cloth - nail polish remover might do.
Make your mix and lay up some patches, alternate the lay of the cloth with each patch.
Four or five patches on and you can add some high density fillers to a mix to make a ' peanut butter' mix to build up the level with the surrounds, then a couple more larger patches to tie the surrounds over the repair...done.
Boat of your boats vintage may well be due some reinforcement around the pot base anyway, while you're in there I'd suggest giving that some love too.
While you're at I'd suggest putting a couple or three wraps completely around the mast pot, bottom to top.
Don't be daunted, it's fiddly and can be awkward but it's well within your reach.
Oh, tape up your deck cut out so you don't rip your arms to bits.
Don't rush, it will come back to haunt you..
Voodoo out


Active Member
Hi Mathia,

After receiving all manner of great tips from the fine folks here on the Laser forum, I started my own mast step re-enforcement project. The first section I pondered a lot on was, "What should I do about the donut?" By looking at quite a few photos of them here, seems like they are all different shapes. So what you end up doing about yours I think depends on it's shape. Here's what I did about mine.

The first photo shows the donut before I did anything. My boat is a 1988 so it's not super old, but you can see how a piece of the donut has already cracked and fallen off. Found it rattling around in the boat shortly after I bought it.


Because my donut had a nice lip on it, I started by getting a screw driver under the lip and gently prying it upward to see how stiff it was. I was surprised at how soft the material was and how the whole donut would flex while doing this test.

So, I decided the donut had to go, but also because of another question; "How the heck am I going to lay glass over all those compound curves!?" I pulled out my cat's paw nail puller, put a little wooden block on the floor of the hull for a better fulcrum point and started to (again, gently) pry under the lip of the donut. And after just a few prys, BAM... a big section broke off. Hmmm, that was easy.

I kept working around the mast tube, getting the same results in the areas where there was a nice lip. But there were sections where there wasn't any kind of lip... kind of what most of your donut looks like... so I got out my dremel, put a small cutting disc on it and carefully cut horizontally grooves from the outside of the donut towards the center. This was pretty easy because the donut material is quite soft.

I then cut vertical grooves to section individual areas off. This allowed me to pop off more sections with a screw driver or the cat's paw. The photo below shows when I had the entire donut removed. And all the pieces.


The next step was making it easier to lay fiberglass cloth over the 90 degree angle that I now had created where the bottom of the mast tube meets the raised square cup where the mast tube was squashed into the donut material. I did this by first doing a simulation outside of the boat as a test. Below is a photo of some 3 1/4 inch diameter PVC pipe set into a hole in two plywood blocks that simulate the stepped mast tube.


You can see where the red arrow is pointing that there's no longer a 90 degree angle at the mast tube and cup junction. It's now two 135 degree angles. The white material is West System epoxy resin (#105) mixed with hardener (#206) that I then added filler (#404) to until it was a peanut butter consistency. I then used a syringe to apply it at the joint and smoothed it to the finish you see here with one of those small foam paint brushes. Now I have a much easier angle to lay the glass over.

One thing I've learned from the experienced folks here when it comes to doing repairs is this. Take Your Time. Don't worry how long it's going to take. Just take your time, think it through and do it right. Because when it comes to the mast step, you want to only have to do the repair/re-enforcement once and be done with it forever.

And I follow Voodoo's detailed advice quite a lot. The guy really knows his stuff. As, it seems, just about all the regulars who post here.

Cheers and good luck!

- Andy
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Voodoo 158546

Hard hiking at the end of a 3hr race, killer
Thanks for the kind words Andy.
Like your advice too - 'specially the 'don't rush, take your time' bit..
Seen/ had to rework so many rush jobs that have just not lasted.
Shortcuts usually end up cutting short

when I am faced with a nasty portion of a fix, one mantra I call on is ' every bit done is a bit less to do'
Do it right, do it once.
I have recently done this repair to my old laser following what was recommended here.

This original repair was done many years ago to the mast step, but the mast step started to leak and water was getting in the boat.
I found the wood doughnut was also wet, so I had to remove some of the old repaired fibreglass cloth to expose the wet wood doughnut, and it was quite wet.

You don't have to remove all the fibreglass around the doughnut; just a couple of square inches, the wood will dry just fine like this.

The doughnut must be dried or the new fibreglass repair won't stick or worst of all the wood doughnut will rot out and weaken the repair.
Get a small desk fan and face it into the deck hatch to push air onto the wet wood, this works best if there is another hatch on your boat to allow cross ventilation.
This took around week to dry.

Cheers Steve
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Thread starter #7
Thanks again for all the help, i have managed to remove half of the donut, and it appears to be rotten or something. I dont know exactly what material it is but it kinda feels like a ceramic of some sort, can this material even rot? My question is, do i need to remove all of the donut now? Or could i just put fiberglass over it, it dosent feel wet or anything, though it is much easier to poke through the rotten bit vs the non rotten. The donut seems solid though, and it takes like forever to remove it.

Thanks for the help :)



Active Member
It wasn't but a few weeks ago that I was right at the point you are Mathia. I also pondered whether I should just leave most of the donut and glass over it. But after thinking about it, I decided to do the extra work and get rid of the big fold of goop... mainly so that the glassing/re-enforcement job would be easier.

As you have found, the donut material is pretty soft. After pondering how to deal with the areas I couldn't pry off with my Cat's Paw, I used my dremel with a small cutting disc and was surprised how easily I could cut the donut material.

The only problem was being able to see the other side of the donut that was hidden behind the mast tube. I was able to use Voodoo's suggestion of a small mirror on a wire and that worked ok... with some limitations. But with the resin and glassing job to come, that was going to require speed, I came up with a far better mirror set up. Here it is.

The only thing I bought was the mirror... for $6 at Walmart. All the other parts I had laying around the house.


What you see is GoPro parts and a dashboard mount for my Garmin Nuvi that I never used in my truck. The mirror is 4 and 3/4 inches in diameter so it fits through the 5 inch diameter hole I cut in the deck. The Nuvi dashboard mount is soft so I just fold in the edges and it fits through the hole too. In fact, I don't even have to take the thing apart. The whole thing fits through the hole. The GoPro parts allow me to adjust the angle of the mirror easily, even with it inside the boat.

The photo below shows why I took the effort to make this Frankenstein Mirror. You can see how well it shows the entire backside of my PVC simulated mast tube.


This will make my glassing project much easier and faster... cause I can see everything now. What I like about the Garmin dashboard mount (it's flexible and heavy... like it's filled with sand) as a base is I can push this thing up the sloped side of the hull inside the boat and forget about it. It won't move. No more holding the mirror and working one handed.

By the way, I was able to pretty easily dremel out the backside of the donut with just a tiny little mirror wiggling around on the end of a wire I was holding with my other hand. With a Frankenstein Mirror type contraption, removing the rest of your donut will be a snap.

But... on Frankenstein Mirror Version 1.0 I used a plastic, rectangular mirror I got at an auto parts store cheap. The only problem was it was convex... designed for a larger field of vision. It didn't work very well at all because it made the back of the mast tube too far away. So don't use a convex mirror.

However, with Frankenstein Mirror Version 1.1, the one you see above, I can see every little detail... even small scratches... on the backside of the mast tube.

My recommendation is to do a bit more work and remove the rest of that pain in the butt donut. Once you have the proper tools, the donut removal job is much faster and easier than it looks.

- Andy
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bringing back an old thread...i am in need to do this repair. i have a few hours worth of sailing experience, and no experiencing repairing fiberglass or boats. Boat is either '73 or '76

I believe I understand the idea behind this: strengthening the mast step so it doesn't break using fiberglass and glue (i.e., epoxy or resin/hardener), please correct me if I am wrong.

1. My mast step also has a leak; will glassing and gluing stop the leak, or do I need to paint the glue over the leak first?
2. what is right material I need (fiberglass, resin or epoxy, etc.) specific brands would be helpful. I've seen a repair kit by West Systems mentioned, as well as other materials, but not sure exactly what would be best to use
3. where can i best find this material (Amazon, marine store, etc.?)?
4. Do i need to wrap the mast step with fiberglass also, even where it meets the deck (i've read that this is good to do also in other posts here)
5. Since I have not worked with these materials, and have done some research, idea is to lay glue, then glass, then glue, then glass. How many layers is sufficient?

help is greatly appreciated! thank you to active members!